ref(JingleSessionPC): send source update upon reconnect
ref(JingleSessionPC): send source update upon reconnect

Given that the XMPP connection is able to reconnect after a drop, now
the jingle session needs to hold off any updates that have to be sent
while the signalling is down. Send the update upon reconnect to sync
Jicofo and JVB with the client's source description.

jitsi/lib-jitsi-meet,jiyeyuran/lib-jitsi-meet,jitsi/lib-jitsi-meet,damencho/lib-jitsi-meet